US3681032A - Carbon content analysis - Google Patents
Carbon content analysis Download PDFInfo
- Publication number
- US3681032A US3681032A US44727A US3681032DA US3681032A US 3681032 A US3681032 A US 3681032A US 44727 A US44727 A US 44727A US 3681032D A US3681032D A US 3681032DA US 3681032 A US3681032 A US 3681032A
- Authority
- US
- United States
- Prior art keywords
- enclosure
- methane
- carbon
- furnace
- hydrogen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title abstract description 27
- 229910052799 carbon Inorganic materials 0.000 title abstract description 27
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 abstract description 78
- 239000001257 hydrogen Substances 0.000 abstract description 22
- 229910052739 hydrogen Inorganic materials 0.000 abstract description 22
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical class [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract description 18
- 239000012466 permeate Substances 0.000 abstract description 5
- 238000005259 measurement Methods 0.000 abstract description 3
- VJYFKVYYMZPMAB-UHFFFAOYSA-N ethoprophos Chemical compound CCCSP(=O)(OCC)SCCC VJYFKVYYMZPMAB-UHFFFAOYSA-N 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 24
- 238000000034 method Methods 0.000 description 11
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 150000002431 hydrogen Chemical class 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910001868 water Inorganic materials 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0011—Sample conditioning
- G01N33/0013—Sample conditioning by a chemical reaction
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N7/00—Analysing materials by measuring the pressure or volume of a gas or vapour
- G01N7/14—Analysing materials by measuring the pressure or volume of a gas or vapour by allowing the material to emit a gas or vapour, e.g. water vapour, and measuring a pressure or volume difference
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/23—Carbon containing
Definitions
- the present invention relates to a device for measuring the carbon content of gas furnace atmospheres.
- the invention provides a device for measuring the carbon content of gas furnace atmospheres which also contain hydrogen, which device comprises an enclosure for insertion into the furnace atmosphere, the enclosure comprising a material which is permeable to hydrogen and in which carbon is both soluble and mobile at the operating temperature whereby methane is formed in the interior of the said enclosure, and means for measuring the production of methane.
- the enclosure may comprise iron, nickel, or their alloys.
- the effective permeability of the carbon is much lower than the effective permeability of hydrogen at the operating temperature, so that there is an excess of hydrogen at the inner surface of the enclosure and all the carbon will be able to react with the hydrogen to form methane.
- the methane concentration can be measured either by a static or a dynamic method, and in the static method the contents of the enclosure are allowed to react so that the methane concentration Within the enclosure is in equilibrium with the carbon concentration at the inner surface of the enclosure.
- the methane is withdrawn from the enclosure at a rate less than that rate at which it is formed and analysed, for example, by means of a 'gas chromatograph.
- the methane concentration within the enclosure is effectively zero and the rate of formation of methane is measuredto give a measure of the carbon activity gradient across the wall of the enclosure and hence the carburising potential within the furnace atmosphere.
- This state of affairs is most easily achieved either by pumping off the methane as it is formed, using either a vacuum system or an inert sweep gas, the term inert being used to mean a gas which does not react with either carbon or hydrogen.
- the sweep gas is conveniently argon.
- SIG. l is a diagrammatic representation of a device
- FIG. 2 is a diagrammatic representation of another device.
- the furnace is represented by 11 and provision for a furnace gas feed is represented by inlet and outlet pipes 12, 13 respectively.
- a metallic enclosure provided by a thin-walled thimble 14 of iron, nickel or an alloy of iron or nickel.
- Pipelines 15, 16 respectively couple the thimble 14 to a supply of inert sweep gas via a standard purification train 17 and, on the outlet side, to a gas chromatograph 18.
- the furnace and thimble being closely similar to the FIG. 1 arrangement, are referenced with the same numerals.
- the thimble 14 differs in FIG. 2 in having only an outlet pipe 19 connected.
- Methane is removed from the thimble 14 as fast as it forms by pumping out using a vacuum system.
- a diffusion pump 21 pumps the methane into a collec tion volume 22, which can be cleared periodically by coupling, via valve 23, with a standard vacuum system 24.
- a pipeline 25, with valve 26, is provided for periodic withdrawal of gas samples for analysis, for example by a gas chromatograph.
- a device for measuring the carbon content of gas furnace atmospheres which also contain hydrogen which device comprises an enclosure for insertion into the furnace atmosphere, the enclosure comprising a material which is permeable to hydrogen and in which carbon is both soluble and mobile at the operating temperature such that hydrogen and carbon from a gas furnace atmosphere will permeate through the material of the enclosure, said enclosure being constructed and arranged such that it is substantially isolated in its interior from any hydrogen other than said permeated hydrogen, whereby methane is formed in the interior of the said enclosure from said permeated hydrogen and carbon, and means for measuring the production of methane so formed.
- a device as claimed in claim 1, wherein the ,en-, closure comprises iron, or an alloy thereof.
- a device as claimed in claim 1, wherein the enclosure comprises nickel, or an alloy thereof.
- a device as claimed in claim 4, wherein the means for withdrawing methane from the enclosure comprise means for driving a flow of sweep gas through the enclosure.
- a vacuum system for withdrawing methane from the enclosure.
- a method of measuring the carbon content of gas furnace atmospheres which also contain hydrogen which comprises inserting into. the furnace atmosphere an enclosure comprising a material which-is permeable to hydrogen and in which carbon isbothsoluble and mobile at the operating temperature suchthat hydrogen and carbon from the gas furnace atmosphere permeate through the material of'the" enclosure,'-maintaining the interior of the enclosure substantially .isolated from any other exterior hydrogen source, whereby methane; is'formed in the interior of the said enclosure from said permeated hydrogen and carbon, and measuring the production of methane soformed.
Abstract
AN ENCLOSURE OF A METAL IN WHICH CARBON IS SOLUBLE AND MOBILE AT THE OPERATING TEMPERATURE IS INSERTED INTO THE GAS ATMOSPHERE OF A FURNACE. HYDROGEN (IN EXCESS) AND CARBON FROM THE FURNACE ATMOSPHERE PERMEATE TO THE INTERIOR OF THE ENCLOSURE AND THERE REACT TO FORM METHANE. MEASUREMENT OF THE METHANE CONCENTRATION IN THE ENCLOSURE PROVIDES AN INDICATION OF CARBON CONTENT IN THE GAS ATMOSPHERE.
Description
United States Patent 3,681,032 CARBON CONTENT ANALYSIS Geoffrey Long, Abingdon, England, assignor to United Kingdom Atomic Energy Authority, London, England Filed June 9, 1970, Ser. No. 44,727 Claims priority, application Great Britain, June 13, 1969, 30,211/ 69 Int. Cl. G0ln 7/10 US. Cl. 23-254 R 10 Claims ABSTRACT OF THE DISCLOSURE An enclosure of a metal in which carbon is soluble and mobile at the operating temperature is inserted into the gas atmosphere of a furnace. Hydrogen (in excess) and carbon from the furnace atmosphere permeate to the interior of the enclosure and there react to form methane. Measurement of the methane concentration in the enclosure provides an indication of carbon content in the gas atmosphere.
BACKGROUND OF THE INVENTION The present invention relates to a device for measuring the carbon content of gas furnace atmospheres.
It is known that when, for example, steel articles have been made, the process of manufacture frequently introduces work hardening which must be relieved, and to this end the articles are normally annealed for an appropriate length of time. The atmosphere in the annealing furnace must be such as to cause no carburising or decarburising of the steel and this atmosphere is normally prow'ded by the incomplete combustion of fuel gas. The atmosphere therefore contains, in practice, methane, carbon monoxide, carbon dioxide, hydrogen and water vapour, the various constituents being present in a complex equilibrium state. In order to ensure that the carburising potential of the atmosphere is correct, it is necessary to measure this potential from time to time but unfortunately this has hitherto proved diflicult, since existing methods, for example chemical analysis of the gas atmosphere, give data which are only indirectly related to the required carburising potential. It is therefore extremely desirable to provide a device for measuring the effective carbon content of the atmosphere within the furnace.
SUMMARY OF THE INVENTION The invention provides a device for measuring the carbon content of gas furnace atmospheres which also contain hydrogen, which device comprises an enclosure for insertion into the furnace atmosphere, the enclosure comprising a material which is permeable to hydrogen and in which carbon is both soluble and mobile at the operating temperature whereby methane is formed in the interior of the said enclosure, and means for measuring the production of methane.
The enclosure may comprise iron, nickel, or their alloys. In these materials, the effective permeability of the carbon is much lower than the effective permeability of hydrogen at the operating temperature, so that there is an excess of hydrogen at the inner surface of the enclosure and all the carbon will be able to react with the hydrogen to form methane.
It will be realised that the reactions taking place within the furnace are equilibrium reactions which can be represented by:
3,681,032 Patented Aug. 1, 1972 The equilibrium positions of these reactions depend upon the redox and carburising potentials within the furnace. It is difficult to withdraw a sample from the furnace atmosphere as at least the second of these equilibrium reactions is liable to change its position during cooling. However, by using the process upon which the present invention is based, the third reaction is caused to take place also within the enclosure and this reaction does not change its equilibrium position on being cooled. Moreover, as explained, there is always an excess of hydrogen present within the enclosure so that, within the enclosure, the reaction is driven in the left-hand direction. These effects are readily calculated so that, by measuring the methane concentration within the enclosure, the carburising potential within the furnace atmosphere can 'be determined.
Essentially, the methane concentration can be measured either by a static or a dynamic method, and in the static method the contents of the enclosure are allowed to react so that the methane concentration Within the enclosure is in equilibrium with the carbon concentration at the inner surface of the enclosure. In practice, the methane is withdrawn from the enclosure at a rate less than that rate at which it is formed and analysed, for example, by means of a 'gas chromatograph.
In the dynamic method, on the other hand, the methane concentration within the enclosure is effectively zero and the rate of formation of methane is measuredto give a measure of the carbon activity gradient across the wall of the enclosure and hence the carburising potential within the furnace atmosphere. This state of affairs is most easily achieved either by pumping off the methane as it is formed, using either a vacuum system or an inert sweep gas, the term inert being used to mean a gas which does not react with either carbon or hydrogen. The sweep gas is conveniently argon.
DESCRIPTION OF PREFERRED EMBODIMENTS Specific constructions of device embodying the invention will now be described by way of example and with reference to the accompanying drawings in which:
SIG. l is a diagrammatic representation of a device, an
FIG. 2 is a diagrammatic representation of another device.
In both examples, measurement of methane concentration is by a dynamic technique.
Referring to FIG. 1, the furnace is represented by 11 and provision for a furnace gas feed is represented by inlet and outlet pipes 12, 13 respectively.
Within the furnace is mounted a metallic enclosure provided by a thin-walled thimble 14 of iron, nickel or an alloy of iron or nickel.
In operation, hydrogen and carbon in the furnace gases permeate through the metal of the thimble 14 and react at the interior of the thimble 14 to form methane. The methane is swept away as fast as it is formed by the sweep gas and analysis for methane concentration made with the gas chromatograph 18. As explained above, the relation ship between this measured methane concentration and the carburising potential of the furnace gases is readily calculated from the known solubility and mobility of carbon in the thimble material at the operating temperature, and the dimensions of the thimble walls.
In the example of FIG. 2, the furnace and thimble, being closely similar to the FIG. 1 arrangement, are referenced with the same numerals. The thimble 14 differs in FIG. 2 in having only an outlet pipe 19 connected.
Methane is removed from the thimble 14 as fast as it forms by pumping out using a vacuum system. p
A diffusion pump 21 pumps the methane into a collec tion volume 22, which can be cleared periodically by coupling, via valve 23, with a standard vacuum system 24. A pipeline 25, with valve 26, is provided for periodic withdrawal of gas samples for analysis, for example by a gas chromatograph.
The invention is not restricted to the details of the foregoing example.
I claim:
1. A device for measuring the carbon content of gas furnace atmospheres which also contain hydrogen, which device comprises an enclosure for insertion into the furnace atmosphere, the enclosure comprising a material which is permeable to hydrogen and in which carbon is both soluble and mobile at the operating temperature such that hydrogen and carbon from a gas furnace atmosphere will permeate through the material of the enclosure, said enclosure being constructed and arranged such that it is substantially isolated in its interior from any hydrogen other than said permeated hydrogen, whereby methane is formed in the interior of the said enclosure from said permeated hydrogen and carbon, and means for measuring the production of methane so formed.
2. A device as claimed in claim 1, wherein the ,en-, closure comprises iron, or an alloy thereof.
3. A device as claimed in claim 1, wherein the enclosure comprises nickel, or an alloy thereof.
4. A device as claimed in claim 1, wherein means are provided for withdrawing methane from the enclosure as fast as it is formed therein and for supplying the methane to means for measuring the methane concentration.
5. A device as claimed in claim 4, wherein the means for withdrawing methane from the enclosure comprise means for driving a flow of sweep gas through the enclosure.
for withdrawing methane from the enclosure comprises a vacuum system.
7. A method of measuring the carbon content of gas furnace atmospheres which also contain hydrogen, which comprises inserting into. the furnace atmosphere an enclosure comprising a material which-is permeable to hydrogen and in which carbon isbothsoluble and mobile at the operating temperature suchthat hydrogen and carbon from the gas furnace atmosphere permeate through the material of'the" enclosure,'-maintaining the interior of the enclosure substantially .isolated from any other exterior hydrogen source, whereby methane; is'formed in the interior of the said enclosure from said permeated hydrogen and carbon, and measuring the production of methane soformed. 1'. v.
8. A method as claimed in claim 7- wherein methane is withdrawn from the enclosure] as. fast 7, as it is formed therein, and is supplied to means for measuring .the'methane concentration.
9. .A method as. claimed in claim 7 wherein methane is withdrawn from the enclosure as fast, as it is formed therein by driving a flow of sweep gas through the en- I closure,'and then the methane is supplied toa means for measuring the methane concentration.
10. A method as claimed in claim 7 wherein methane is Withdrawn from the enclosure as fast as it is formed therein .by means ofa vacuum system,.and then the methane is supplied to a means for measuring the methane 6. A device as claimed in claim 4, wherein the means 40 concentration, 1 References Cited UNITED STATES PATENTS" 2,909,919 10/1959 M er 73-23 3,451,256 6/1969 Kolodney 23- 254 R MORRISO. WOLK, Primary Examiner R. M. REESE, Assistant Examiner I us. :1. X.R. f 23-232 R; 73 19, 23. I
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3021169 | 1969-06-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3681032A true US3681032A (en) | 1972-08-01 |
Family
ID=10304047
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US44727A Expired - Lifetime US3681032A (en) | 1969-06-13 | 1970-06-09 | Carbon content analysis |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US3681032A (en) |
| GB (1) | GB1309549A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3942357A (en) * | 1974-05-02 | 1976-03-09 | Anthony Jenkins | Inspection apparatus |
| US4463593A (en) * | 1980-11-11 | 1984-08-07 | G. D. Searle & Co. | Apparatus for monitoring the partial pressure of gases |
| US4541268A (en) * | 1981-09-23 | 1985-09-17 | Bruker-Franzen Analytik Gmbh | Method and device for the sampling of trace elements in gases, liquids, solids or in surface layers |
| CN104964894A (en) * | 2015-07-29 | 2015-10-07 | 辽宁工程技术大学 | Method for determining content of hydrogen sulfide of coal bed |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114674773B (en) * | 2022-05-30 | 2022-12-23 | 深圳市道合顺传感实业有限公司 | Rapid nondestructive testing device and nondestructive testing method for formaldehyde emission |
-
1969
- 1969-06-13 GB GB3021169A patent/GB1309549A/en not_active Expired
-
1970
- 1970-06-09 US US44727A patent/US3681032A/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3942357A (en) * | 1974-05-02 | 1976-03-09 | Anthony Jenkins | Inspection apparatus |
| US4463593A (en) * | 1980-11-11 | 1984-08-07 | G. D. Searle & Co. | Apparatus for monitoring the partial pressure of gases |
| US4541268A (en) * | 1981-09-23 | 1985-09-17 | Bruker-Franzen Analytik Gmbh | Method and device for the sampling of trace elements in gases, liquids, solids or in surface layers |
| CN104964894A (en) * | 2015-07-29 | 2015-10-07 | 辽宁工程技术大学 | Method for determining content of hydrogen sulfide of coal bed |
Also Published As
| Publication number | Publication date |
|---|---|
| GB1309549A (en) | 1973-03-14 |
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